This invention relates to a reinforcement constituting the bumper of an automotive vehicle.
For reasons of design, there has recently been an increase in the number automotive vehicles in which the parking lamps are accommodated in the corners of a bumper, as shown in FIG. 1. In order to secure the space needed for accommodating these lamps, part of the bumper shell and reinforcement must be cut away. This not only diminishes the collision strength of the bumper corner but also leads to possible lamp damage at the time of a collision.
FIG. 7 illustrates the structure of a conventional bumper made of resin, as disclosed in the specification of Japanese Pat. Application Laid-Open (KOKAI) No.58-177747. In the example shown in FIG. 7, a turn-signal lamp 22 is fitted in a bumper 21, in which case a shock absorber 24 is provided in the front portion of a reinforcement 23 having a generally rectangular cross section. The surface of the shock absorber 24 is covered by a bumper shell, and there are provided a lamp accommodating recess 26 and an engaging hole 28 for fixing an external cylinder 27. An opening 29 for preventing interference of the external cylinder 27 is provided to the rear of the engaging hole 28, and the surface of an opening 30 provided in the front wall of the reinforcement 23 is covered by a covering portion 32.
FIG. 8 illustrates a conventional automobile bumper disclosed in the specification of Japanese Utility Model Publication (KOKOKU) No. 59-43149. The back side of a bumper body 23 is provided with a reinforcing plate 34 extending over the entire length of the bumper in the width direction of the vehicle. The reinforcing plate 34 is provided with a through-hole 36 at a portion thereof joined to a bumper stay 35, and a mounting piece 37 for effecting mounting to the reinforcing plate is provided with a hollowed-out portion 38. Numeral 39 denotes a lamp.
FIG. 9 shows a conventional vehicle bumper disclosed in the specification of Japanese Pat. Publication (KOKOKU) No. 60-30570. Here a lamp assembly 41 attached to a bumper 40 has a housing 42 fixed to the upper plate of a beam 43. Numeral 44 denotes a lamp body capable of sliding along a guide groove 46 provided in a side wall 45 of the housing 42. Numeral 47 denotes a lens having a lamp 48 and a socket 49 disposed on the inner side of the lens. Numeral 50 denotes a spring connecting the housing 42 to a retaining lug of the lamp body 44.
With the bumper structure of FIG. 7, damage to the outer cylindrical body 27 of the turn-signal lamp 22 at the time of a collision is prevented by the shock absorber 24 and the covering portion 32 of the front wall 31 of reinforcement 23. However, it is almost impossible for the signal lamp 22 to recede accurately in the central direction of the vehicle at the time of a collision, and the outer cylinder 27 encountered interference from a peripheral flange 31a of the reinforcement 23. Though the flange portion 31a has the covering portion 32, the latter is soft for the purpose of providing protection. Consequently, when the outer cylinder 27 encounters interference, the covering portion 32 is compressed and therefore hardened. As a result, suitable protection cannot be provided and the outer cylinder 27 may be damaged at impact.
In the automobile bumper of FIG. 8, the lamp 39 attached to the bumper body 33 is shifted to the rear at the time of impact, but the reinforcing plate 34 on the back side of the bumper body 33 curves in the rearward direction to produce a space that allows movement, thereby preventing damage. However, since the bumper body 33 is made of a synthetic resin, it undergoes a large amount of change at impact and the lamp 39 interferes with the periphery of the through-hole 36, as a result of which the lamp is damaged. Though this problem can be solved if the space S is enlarged, this is difficult in terms of the vehicle structure.
In the case of the vehicle bumper shown in FIG. 9, the lamp assembly 41 is displaced at the time of a collision, after which it is restored to its original position by the spring 50. Since this structure constitutes a single unit, it is very complex and high in cost.